| ( | x | + | 215 | ) | ( | x | + | 215 | ) | = | 500 | × | 500 | + | ( | x | + | 303 10 | − | 20 | ) | ( | x | + | 303 10 | − | 20 | ) |
| 方程左边 = | x | ( | x | + | 215 | ) | + | 215 | ( | x | + | 215 | ) |
| = | x | x | + | x | × | 215 | + | 215 | ( | x | + | 215 | ) |
| = | x | x | + | 215 | x | + | 215 | x | + | 215 | × | 215 |
| = | x | x | + | 215 | x | + | 215 | x | + | 46225 |
| = | x | x | + | 430 | x | + | 46225 |
| x | x | + | 430 | x | + | 46225 | = | 500 | × | 500 | + | ( | x | + | 303 10 | − | 20 | ) | ( | x | + | 303 10 | − | 20 | ) |
| 方程右边 = | 250000 | + | ( | x | + | 303 10 | − | 20 | ) | ( | x | + | 303 10 | − | 20 | ) |
| x | x | + | 430 | x | + | 46225 | = | 250000 | + | ( | x | + | 303 10 | − | 20 | ) | ( | x | + | 303 10 | − | 20 | ) |
| 方程右边 = | 250000 | + | x | ( | x | + | 303 10 | − | 20 | ) | + | 303 10 | ( | x | + | 303 10 | − | 20 | ) | − | 20 | ( | x | + | 303 10 | − | 20 | ) |
| = | 250000 | + | x | x | + | x | × | 303 10 | − | x | × | 20 | + | 303 10 | ( | x | + | 303 10 | − | 20 | ) | − | 20 | ( | x | + | 303 10 | − | 20 | ) |
| = | 250000 | + | x | x | + | 103 10 | x | + | 303 10 | ( | x | + | 303 10 | − | 20 | ) | − | 20 | ( | x | + | 303 10 | − | 20 | ) |
| = | 250000 | + | x | x | + | 103 10 | x | + | 303 10 | x | + | 303 10 | × | 303 10 | − | 303 10 | × | 20 | − | 20 |
| = | 250000 | + | x | x | + | 103 10 | x | + | 303 10 | x | + | 91809 100 | − | 606 | − | 20 | ( | x | + | 303 10 | − | 20 | ) |
| = | 25031209 100 | + | x | x | + | 203 5 | x | − | 20 | ( | x | + | 303 10 | − | 20 | ) |
| = | 25031209 100 | + | x | x | + | 203 5 | x | − | 20 | x | − | 20 | × | 303 10 | + | 20 | × | 20 |
| = | 25031209 100 | + | x | x | + | 203 5 | x | − | 20 | x | − | 606 | + | 400 |
| = | 25010609 100 | + | x | x | + | 103 5 | x |
| x | x | + | 430 | x | + | 46225 | = | 25010609 100 | + | x | x | + | 103 5 | x |